agg-gui 0.2.0

//! Widget inspector panel — uses the system `TreeView` for tree display.
//!
//! Layout (Y-up, panel fills its full bounds):
//! ```text
//! ┌─────────────────────┐ ← top (HEADER_H)   header (painted monolithically)
//! ├─────────────────────┤
//! │   TreeView          │ ← tree area (TreeView painted here)
//! ├╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌┤ ← draggable h-split
//! │   Properties        │ ← props area (painted monolithically)
//! └─────────────────────┘ ← bottom (y=0)
//! ```

mod widget_impl;

use std::cell::RefCell;
use std::rc::Rc;
use std::sync::Arc;

use crate::color::Color;
use crate::draw_ctx::DrawCtx;
use crate::event::{Event, EventResult};
use crate::geometry::{Point, Rect, Size};
use crate::layout_props::{HAnchor, Insets, VAnchor, WidgetBase};
use crate::text::Font;
use crate::widget::{InspectorNode, InspectorOverlay, Widget};
use crate::widgets::tree_view::TreeView;

// ── InternalPresenceNode ──────────────────────────────────────────────────────

/// Transparent placeholder child representing the inspector's internal `TreeView`
/// in the widget inspector tree.
///
/// This makes `InspectorPanel` appear as an expandable node (with one child) in
/// the inspector rather than a leaf, so the user can see that the panel contains
/// an internal tree.
///
/// Hit-test is always `false` (no event interception).  Paint is a no-op (the
/// real `TreeView` is painted directly by `InspectorPanel`).
/// `contributes_children_to_inspector` returns `false` to stop the inspector
/// from recursing into row_widgets, which would grow the node list exponentially.
///
/// Bounds are kept in sync with the real `TreeView` by `InspectorPanel::layout`.
struct InternalPresenceNode {
    bounds: Rect,
    children: Vec<Box<dyn Widget>>,
    base: WidgetBase,
    name: &'static str,
}

impl Widget for InternalPresenceNode {
    fn type_name(&self) -> &'static str {
        self.name
    }
    fn bounds(&self) -> Rect {
        self.bounds
    }
    fn set_bounds(&mut self, b: Rect) {
        self.bounds = b;
    }
    fn children(&self) -> &[Box<dyn Widget>] {
        &self.children
    }
    fn children_mut(&mut self) -> &mut Vec<Box<dyn Widget>> {
        &mut self.children
    }
    fn margin(&self) -> Insets {
        self.base.margin
    }
    fn widget_base(&self) -> Option<&WidgetBase> {
        Some(&self.base)
    }
    fn widget_base_mut(&mut self) -> Option<&mut WidgetBase> {
        Some(&mut self.base)
    }
    fn h_anchor(&self) -> HAnchor {
        self.base.h_anchor
    }
    fn v_anchor(&self) -> VAnchor {
        self.base.v_anchor
    }
    fn min_size(&self) -> Size {
        self.base.min_size
    }
    fn max_size(&self) -> Size {
        self.base.max_size
    }
    fn layout(&mut self, _: Size) -> Size {
        Size::new(self.bounds.width, self.bounds.height)
    }
    fn paint(&mut self, _: &mut dyn DrawCtx) {}
    fn hit_test(&self, _: Point) -> bool {
        false
    }
    fn on_event(&mut self, _: &Event) -> EventResult {
        EventResult::Ignored
    }
    fn contributes_children_to_inspector(&self) -> bool {
        false
    }
}

// ── geometry constants ────────────────────────────────────────────────────────
const DEFAULT_PROPS_H: f64 = 180.0;
pub(super) const FONT_SIZE: f64 = 12.0;
const HEADER_H: f64 = 30.0;
const SPLIT_HIT: f64 = 5.0;
const MIN_PROPS_H: f64 = 60.0;
const MIN_TREE_H: f64 = 60.0;

// ── light theme colors ────────────────────────────────────────────────────────
// Theme-aware colour helpers — all derive from the active `Visuals` so the
// inspector follows light / dark mode changes without a restart.
fn c_panel_bg(v: &crate::theme::Visuals) -> Color {
    v.panel_fill
}
fn c_header_bg(v: &crate::theme::Visuals) -> Color {
    // Slightly darker than the panel fill.
    let f = if is_dark(v) { 0.80 } else { 0.94 };
    Color::rgba(
        v.panel_fill.r * f,
        v.panel_fill.g * f,
        v.panel_fill.b * f,
        1.0,
    )
}
fn c_props_bg(v: &crate::theme::Visuals) -> Color {
    v.window_fill
}
fn c_split_bg(v: &crate::theme::Visuals) -> Color {
    let t = if is_dark(v) { 1.0 } else { 0.0 };
    Color::rgba(t, t, t, 0.10)
}
pub(super) fn c_border(v: &crate::theme::Visuals) -> Color {
    v.separator
}
pub(super) fn c_text(v: &crate::theme::Visuals) -> Color {
    v.text_color
}
pub(super) fn c_dim_text(v: &crate::theme::Visuals) -> Color {
    v.text_dim
}

fn is_dark(v: &crate::theme::Visuals) -> bool {
    // Panel fill luminance — below 0.5 means we're in a dark palette.
    let lum = 0.299 * v.panel_fill.r + 0.587 * v.panel_fill.g + 0.114 * v.panel_fill.b;
    lum < 0.5
}

// ── event translation helper ──────────────────────────────────────────────────

/// Translate the Y coordinate of a mouse event by subtracting `offset_y`.
/// X is unchanged. Non-mouse events pass through unchanged.
fn translate_event(event: &Event, offset_y: f64) -> Event {
    match event {
        Event::MouseDown {
            pos,
            button,
            modifiers,
        } => Event::MouseDown {
            pos: Point::new(pos.x, pos.y - offset_y),
            button: *button,
            modifiers: *modifiers,
        },
        Event::MouseMove { pos } => Event::MouseMove {
            pos: Point::new(pos.x, pos.y - offset_y),
        },
        Event::MouseUp {
            pos,
            button,
            modifiers,
        } => Event::MouseUp {
            pos: Point::new(pos.x, pos.y - offset_y),
            button: *button,
            modifiers: *modifiers,
        },
        Event::MouseWheel {
            pos,
            delta_y,
            delta_x,
            modifiers,
        } => Event::MouseWheel {
            pos: Point::new(pos.x, pos.y - offset_y),
            delta_y: *delta_y,
            delta_x: *delta_x,
            modifiers: *modifiers,
        },
        other => other.clone(),
    }
}

// ── InspectorPanel ────────────────────────────────────────────────────────────

pub struct InspectorPanel {
    bounds: Rect,
    /// Contains exactly one `InternalPresenceNode` (a transparent proxy for the
    /// internal `TreeView`).  This makes InspectorPanel non-leaf in the inspector
    /// so the user can see it has internal structure.
    _children: Vec<Box<dyn Widget>>,
    base: WidgetBase,
    font: Arc<Font>,
    nodes: Rc<RefCell<Vec<InspectorNode>>>,
    /// Selected: original node index; synced from TreeView selection.
    selected: Option<usize>,
    props_h: f64,
    split_dragging: bool,
    /// Written by layout(); read by the render loop to draw an overlay.
    pub hovered_bounds: Rc<RefCell<Option<InspectorOverlay>>>,
    /// The tree widget, managed directly (not in children).
    pub(crate) tree_view: TreeView,
    /// Set by `apply_saved_state`; consumed on the next layout rebuild so
    /// restored expand / select flags apply even on the very first frame
    /// (before the user has interacted with the tree).
    pending_expanded: Option<Vec<bool>>,
    pending_selected: Option<Option<usize>>,
    /// When bound, each `layout()` writes the current state into this cell
    /// so the harness can persist it without needing mutable access to the
    /// widget tree.
    snapshot_out: Option<Rc<RefCell<Option<InspectorSavedState>>>>,
    /// Edit queue — clicks on reflected property rows push
    /// [`crate::widget::InspectorEdit`] entries here; the host frame loop
    /// drains and applies them via [`crate::widget::apply_inspector_edit`].
    /// Holds mouse-down coords so the click handler in `on_event` can locate
    /// which property row was hit when the layout next paints.
    #[cfg(feature = "reflect")]
    pub edits: Option<Rc<RefCell<Vec<crate::widget::InspectorEdit>>>>,
    /// Queue for WidgetBase live-edits (margin, anchors).  Not gated on
    /// `reflect` — available on every widget via `widget_base_mut`.
    pub base_edits: Option<Rc<RefCell<Vec<crate::widget::WidgetBaseEdit>>>>,
    /// Cached row hit-rectangles built during paint (panel-local bounds);
    /// each entry is `(rect, field_name, row_kind)`.  Used by `on_event` to
    /// translate a click to a queued edit.
    prop_hits: Vec<PropHit>,
    /// Fingerprint of the `inspector_nodes` Vec we last rebuilt the
    /// `TreeView` from — `(data ptr as usize, len)`.  When the harness
    /// skips its snapshot pass (e.g. during a window-resize drag), the
    /// Vec is reused and the ptr stays the same; we then skip the
    /// per-frame `tree_view.nodes` rebuild too, so the tree's row
    /// widgets reuse their backbuffers and the resize stays cheap.
    last_inspector_nodes_fingerprint: Option<(usize, usize)>,
}

#[derive(Clone, Debug)]
#[cfg_attr(not(feature = "reflect"), allow(dead_code))]
pub(super) struct PropHit {
    pub(super) rect: Rect,
    pub(super) field: String,
    pub(super) kind: PropHitKind,
}

#[derive(Clone, Debug)]
pub(super) enum PropHitKind {
    /// Clicking flips the bool (widget-specific reflected field).
    #[cfg_attr(not(feature = "reflect"), allow(dead_code))]
    BoolToggle { current: bool },
    /// Clicking the left half decrements, right half increments (reflected field).
    #[cfg_attr(not(feature = "reflect"), allow(dead_code))]
    NumericStep { current: f64, step: f64 },
    /// Click left half → subtract step from an Insets side; right half → add.
    InsetField {
        target: InsetsTarget,
        side: InsetsSide,
        current: f64,
        step: f64,
    },
    /// Click anywhere on the row to advance to the next HAnchor preset.
    HAnchorCycle { current_bits: u8 },
    /// Click anywhere on the row to advance to the next VAnchor preset.
    VAnchorCycle { current_bits: u8 },
}

/// Which Insets struct the edit targets.
#[derive(Clone, Copy, Debug)]
pub(super) enum InsetsTarget {
    Margin,
    // Padding editing not yet supported (stored differently per container).
}

/// Which side of the Insets to update.
#[derive(Clone, Copy, Debug)]
pub(super) enum InsetsSide {
    Left,
    Right,
    Top,
    Bottom,
}

/// Serializable inspector UI state — apply at startup, snapshot at shutdown.
#[derive(Clone, Debug, Default)]
#[cfg_attr(feature = "reflect", derive(bevy_reflect::Reflect))]
pub struct InspectorSavedState {
    pub expanded: Vec<bool>,
    pub selected: Option<usize>,
    pub props_h: f64,
}

impl InspectorPanel {
    pub fn new(
        font: Arc<Font>,
        nodes: Rc<RefCell<Vec<InspectorNode>>>,
        hovered_bounds: Rc<RefCell<Option<InspectorOverlay>>>,
    ) -> Self {
        let tree_view = TreeView::new(Arc::clone(&font))
            .with_row_height(20.0)
            .with_font_size(12.0)
            .with_indent_width(14.0)
            .with_hover_repaint(false);
        Self {
            bounds: Rect::default(),
            _children: vec![Box::new(InternalPresenceNode {
                bounds: Rect::default(),
                children: Vec::new(),
                base: WidgetBase::new(),
                name: "TreeView",
            })],
            base: WidgetBase::new(),
            font,
            nodes,
            selected: None,
            props_h: DEFAULT_PROPS_H,
            split_dragging: false,
            hovered_bounds,
            tree_view,
            #[cfg(feature = "reflect")]
            edits: None,
            base_edits: None,
            prop_hits: Vec::new(),
            pending_expanded: None,
            pending_selected: None,
            snapshot_out: None,
            last_inspector_nodes_fingerprint: None,
        }
    }

    /// Bind an output cell that the inspector updates every layout with
    /// the current [`InspectorSavedState`] — use the cell from a harness
    /// that persists app state.
    pub fn with_snapshot_cell(mut self, cell: Rc<RefCell<Option<InspectorSavedState>>>) -> Self {
        self.snapshot_out = Some(cell);
        self
    }

    /// Bind a queue the inspector pushes [`crate::widget::WidgetBaseEdit`]s
    /// into when the user edits margin, anchor, or size-constraint fields.
    /// The host frame loop drains and applies via
    /// [`crate::widget::apply_widget_base_edit`].
    pub fn with_base_edit_queue(
        mut self,
        cell: Rc<RefCell<Vec<crate::widget::WidgetBaseEdit>>>,
    ) -> Self {
        self.base_edits = Some(cell);
        self
    }

    /// Bind a queue the inspector pushes [`crate::widget::InspectorEdit`]s
    /// into when the user clicks an editable property value.  The host frame
    /// loop is responsible for draining and applying via
    /// [`crate::widget::apply_inspector_edit`] — doing it inline would
    /// violate the immutable-tree-during-event contract.
    #[cfg(feature = "reflect")]
    pub fn with_edit_queue(
        mut self,
        cell: Rc<RefCell<Vec<crate::widget::InspectorEdit>>>,
    ) -> Self {
        self.edits = Some(cell);
        self
    }

    // ── Persistence helpers ──────────────────────────────────────────────────
    //
    // The platform harness calls `saved_state` at shutdown and
    // `apply_saved_state` on startup so the inspector's tree expand /
    // selection / split-bar position survive restarts.  Values are stored
    // by the position they occupy in the flat DFS tree — if the widget
    // tree differs across runs the worst case is a few extra collapsed
    // nodes, never a crash.

    /// Snapshot the current inspector UI state for persistence.
    pub fn saved_state(&self) -> InspectorSavedState {
        InspectorSavedState {
            expanded: self.tree_view.nodes.iter().map(|n| n.is_expanded).collect(),
            selected: self.tree_view.nodes.iter().position(|n| n.is_selected),
            props_h: self.props_h,
        }
    }

    /// Apply a previously-saved state.  Must be called before the first
    /// `layout()` runs — the inspector restores the expand / select flags
    /// from here when it first rebuilds the TreeView, via the `pending_*`
    /// side channels.
    pub fn apply_saved_state(&mut self, s: InspectorSavedState) {
        self.pending_expanded = Some(s.expanded);
        self.pending_selected = Some(s.selected);
        self.props_h = s.props_h.clamp(MIN_PROPS_H, 1024.0);
    }

    // ── geometry helpers ──────────────────────────────────────────────────────

    /// Height of the area below the header (tree + props).
    fn list_area_h(&self) -> f64 {
        (self.bounds.height - HEADER_H).max(0.0)
    }

    /// Y position of the tree/props split line (from panel bottom).
    fn split_y(&self) -> f64 {
        self.props_h.clamp(
            MIN_PROPS_H,
            (self.list_area_h() - MIN_TREE_H).max(MIN_PROPS_H),
        )
    }

    /// Bottom Y of the tree area (just above the split handle).
    fn tree_origin_y(&self) -> f64 {
        self.split_y() + 4.0
    }

    fn on_split_handle(&self, pos: Point) -> bool {
        let sy = self.split_y();
        pos.y >= sy - SPLIT_HIT && pos.y <= sy + SPLIT_HIT
    }

    fn pos_in_tree_area(&self, pos: Point) -> bool {
        let tree_bot = self.tree_origin_y();
        let tree_top = self.list_area_h();
        pos.y >= tree_bot && pos.y <= tree_top
    }

    /// Forward event to the TreeView, translating Y into tree-local coordinates.
    fn forward_to_tree(&mut self, event: &Event) -> EventResult {
        // tree_view.bounds().y is tree_origin_y() in panel-local space — subtracting
        // it converts panel-local Y to TreeView-local Y (where y=0 is the bottom of
        // the tree area).
        let offset_y = self.tree_view.bounds().y;
        let translated = translate_event(event, offset_y);
        self.tree_view.on_event(&translated)
    }

    fn update_hovered_bounds_from_tree(&self) {
        let nodes = self.nodes.borrow();
        let next = self
            .tree_view
            .hovered_node_idx()
            .and_then(|i| nodes.get(i))
            .map(|n| InspectorOverlay {
                bounds: n.screen_bounds,
                margin: n.margin,
                padding: n.padding,
            });
        let mut hovered = self.hovered_bounds.borrow_mut();
        if *hovered != next {
            *hovered = next;
            crate::animation::request_draw_without_invalidation();
        }
    }
}

// ── Anchor cycle helpers ──────────────────────────────────────────────────────

fn next_h_anchor(bits: u8) -> HAnchor {
    // Cycle: FIT → STRETCH → LEFT → CENTER → RIGHT → FIT
    if bits == HAnchor::FIT.bits()     { HAnchor::STRETCH }
    else if bits == HAnchor::STRETCH.bits() { HAnchor::LEFT }
    else if bits == HAnchor::LEFT.bits()    { HAnchor::CENTER }
    else if bits == HAnchor::CENTER.bits()  { HAnchor::RIGHT }
    else                                    { HAnchor::FIT }
}

fn next_v_anchor(bits: u8) -> VAnchor {
    // Cycle: FIT → STRETCH → BOTTOM → CENTER → TOP → FIT
    if bits == VAnchor::FIT.bits()     { VAnchor::STRETCH }
    else if bits == VAnchor::STRETCH.bits() { VAnchor::BOTTOM }
    else if bits == VAnchor::BOTTOM.bits()  { VAnchor::CENTER }
    else if bits == VAnchor::CENTER.bits()  { VAnchor::TOP }
    else                                    { VAnchor::FIT }
}

// ── Widget impl ───────────────────────────────────────────────────────────────

impl InspectorPanel {
    pub fn with_margin(mut self, m: Insets) -> Self {
        self.base.margin = m;
        self
    }
    pub fn with_h_anchor(mut self, h: HAnchor) -> Self {
        self.base.h_anchor = h;
        self
    }
    pub fn with_v_anchor(mut self, v: VAnchor) -> Self {
        self.base.v_anchor = v;
        self
    }
    pub fn with_min_size(mut self, s: Size) -> Self {
        self.base.min_size = s;
        self
    }
    pub fn with_max_size(mut self, s: Size) -> Self {
        self.base.max_size = s;
        self
    }
}

// ── properties pane ──────────────────────────────────────────────────────────
// Implementation lives in `inspector_props.rs` to keep this file under the
// project line limit.

impl InspectorPanel {
    fn paint_properties(&mut self, ctx: &mut dyn DrawCtx, available_h: f64) {
        let panel_y_offset = 0.0; // properties pane sits at panel-local y=0
        self.prop_hits.clear();
        super::inspector_props::paint_properties(
            ctx,
            available_h,
            panel_y_offset,
            self.bounds.width,
            &self.font,
            self.selected,
            &self.nodes.borrow(),
            &mut self.prop_hits,
        );
    }

    /// Test a click against the property rows for WidgetBase fields (margin,
    /// anchor).  Returns `true` if a `WidgetBaseEdit` was queued.  Not gated
    /// on `reflect` — uses `widget_base_mut` which is always available.
    fn try_emit_base_edit_from_click(&self, pos: Point) -> bool {
        let Some(queue) = &self.base_edits else {
            return false;
        };
        let Some(sel_idx) = self.selected else {
            return false;
        };
        let nodes = self.nodes.borrow();
        let Some(node) = nodes.get(sel_idx) else {
            return false;
        };
        let Some(hit) = self.prop_hits.iter().find(|h| {
            pos.x >= h.rect.x
                && pos.x <= h.rect.x + h.rect.width
                && pos.y >= h.rect.y
                && pos.y <= h.rect.y + h.rect.height
        }) else {
            return false;
        };
        let field = match &hit.kind {
            PropHitKind::InsetField {
                target: InsetsTarget::Margin,
                side,
                current,
                step,
            } => {
                let mid = hit.rect.x + hit.rect.width * 0.5;
                let new_v = (if pos.x < mid {
                    *current - *step
                } else {
                    *current + *step
                })
                .max(0.0);
                match side {
                    InsetsSide::Left => crate::widget::WidgetBaseField::MarginLeft(new_v),
                    InsetsSide::Right => crate::widget::WidgetBaseField::MarginRight(new_v),
                    InsetsSide::Top => crate::widget::WidgetBaseField::MarginTop(new_v),
                    InsetsSide::Bottom => crate::widget::WidgetBaseField::MarginBottom(new_v),
                }
            }
            PropHitKind::HAnchorCycle { current_bits } => {
                crate::widget::WidgetBaseField::HAnchor(next_h_anchor(*current_bits))
            }
            PropHitKind::VAnchorCycle { current_bits } => {
                crate::widget::WidgetBaseField::VAnchor(next_v_anchor(*current_bits))
            }
            _ => return false,
        };
        queue.borrow_mut().push(crate::widget::WidgetBaseEdit {
            path: node.path.clone(),
            field,
        });
        crate::animation::request_draw();
        true
    }

    /// Test a panel-local click against the cached property-row rectangles
    /// painted last frame.  Returns true if the click produced a queued edit.
    #[cfg(feature = "reflect")]
    fn try_emit_edit_from_click(&self, pos: Point) -> bool {
        let Some(queue) = &self.edits else { return false };
        let Some(sel_idx) = self.selected else {
            return false;
        };
        let nodes = self.nodes.borrow();
        let Some(node) = nodes.get(sel_idx) else {
            return false;
        };
        let Some(hit) = self
            .prop_hits
            .iter()
            .find(|h| pos.x >= h.rect.x

                && pos.x <= h.rect.x + h.rect.width
                && pos.y >= h.rect.y
                && pos.y <= h.rect.y + h.rect.height)
        else {
            return false;
        };

        let edit = match &hit.kind {
            PropHitKind::BoolToggle { current } => crate::widget::InspectorEdit {
                path: node.path.clone(),
                field_path: hit.field.clone(),
                new_value: Box::new(!*current),
            },
            PropHitKind::NumericStep { current, step } => {
                let mid = hit.rect.x + hit.rect.width * 0.5;
                let new_v = if pos.x < mid {
                    *current - *step
                } else {
                    *current + *step
                };
                crate::widget::InspectorEdit {
                    path: node.path.clone(),
                    field_path: hit.field.clone(),
                    new_value: Box::new(new_v),
                }
            }
            _ => return false,
        };
        queue.borrow_mut().push(edit);
        crate::animation::request_draw();
        true
    }
}